STUPID QUESTION!!

Where do I start to get Zeid trust spell? I've looked all around on forums and such but haven't found any information.

You have to buy it for 500 login campaign points from the Greeter moogle in Port Bastok to the right of the Moghouses.

You get Zeid from the login campaign. 500 login points from a greeter moogle.

Get the Cipher Of Zeid's Alter Ego using your log in points. Then, trade it to one of the NPCs used to join the trust initiative (Clarion Star, Gondebaud, or Wetata).

Congratz, you now have Zeid.

I should also point out that when you choose the reward from the Greeter Moogle, you'll receive a Cipher.

To actually learn the trust spell, you need trade the Cipher to any one of the three Trust quest starter NPC's (Clarion Star in Port Bastok, Gondebaud in Southern San d'Oria, or Wetata in Windurst Woods).

Whichever of the above three NPC's you choose to trade the Cipher to, keep in mind that you must have completed their starter quest before they will accept the Cipher and give you access to Zeid.